The present invention relates to a floor covering tile to be laid on a floor ground surface of a building or the like so as to form a finished floor surface, and particularly aims to obtain a floor covering tile having a structure of a lamination of a surface layer of soft vinyl chloride resin and a basic layer of thermoplastic resin and having a gently concave lower surface so as to have a stable flat-surface laying property.
It is known to form a water-proof decoratively finished floor surface by adhesively attaching linoleum sheets, asphalt sheets, synthetic resin sheets, or tiles to an indoor or outdoor floor ground surface. This technique has a disadvantage in that it takes a relatively long time for the application and hardening of the adhesive, and it is troublesome to renew sheets. A floor covering tile, which is laid on a floor without using an adhesive, has been proposed (for example, Japanese Utility Model Unexamined Publication No. 63-30534) for the purpose of avoiding this disadvantage.
The conventional floor tile is flat and plate-like so as to form a smooth finished surface on a floor ground surface. In the case where the floor tiles are only laid on the floor, however, the floor tiles are often displaced by a local load due to a walker, movement of fixtures, setting up of a weight matter, or the like, so that edge portions of the tiles are easily curved upward. This tendency increases particularly in the case of floor tiles having soft elasticity, such as those used to improve the feel of walking thereon or to provide sound-proofing. Accordingly, it is necessary to form a complicated anti-displacement mechanism, and it is necessary to suitably adjust butting pressure in laying the floor tiles, so that the work becomes troublesome and the working cost increases.